We do question the validity of claims, but when it comes to takedowns of copyright related content, we simply do not have the resources to throw money at lawyers to evaluate this in detail. We can apply common sense to determine if something appears to be a reasonable request, but we can't pay a lawyer to evaluate every single request. We also can't afford going to court over every case, even if we were to win, because those processes take large amounts of personal time and have a risk of significant penalties.
Legal advocates on Lemmy or any other platform for that matter are not a substitution for legal council.